Method of making insulator caps



IlllllzfI/ B. A, PLIMPTON METHOD 0F MAKING INSULATOR CAPS Filed Aug. 6, 1930 Mmh 21, 1933.

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v attenua* Patented Mar. 21, 1933 BENTLEY A. PLIMPTON, OF BALTIMORE,

MARYLAND, ASSIGNOR TO LOCKE INSULATOR CORPORATION, OF BALTIMORE, MARYLAND, A CORPORATIONV OF MARYLAND METHOD 0F MAKING INSULATOR CAPS Application filed .August 6, 1930. Serial No. 473,491.

The invention relates to the metal caps of insulators, particularly those of the post or post pedestal type and has for its general object the provision of a novel cap and a method of making the same by pressing or stamping from a single piece of material in contradistinction to forging or casting as is the common practice.

An important object of the invention is to provide a method of making a malleable cap in three operations or steps so that the cost of reduction will be reduced to the minimum.

Another object of the invention is to provide a cap constructed by this method and which will be superior to the ordinary variety in point of elasticity, thermal yieldability and non-liability to fracture as its malleable nature, it being formed as a stamping, will preclude brittleness.

To the attainment of the foregoing objects and advantages, the invention preferably consists in the cap construction and method steps to be hereinafter more fully described and claimed, and illustrated in the accompanying drawing in which:

Figure 1 is a view half in elevation and half in section showing the result of the first method step,

Figure 2 is a similar view showing the result of the second step, and

Figure 3 is a view of a similar nature showing the result of the third and final step.

In the actual carrying out of the invention use is necessarily made of suitable dies, male and female, which are not here disclosed but the character of which will be obvious from` an inspection of the drawing. In the first place, a suitable piece, sheet or block of material of a malleable nature is placed within the female die and subjected to pressure by the male die so that the material will be forced into the cup shape shown in Figure 1. This figure shows a cap 1() in inverted position with a flat disk-like top portion 11 at the bottom from which extends a peripheral flange 12 which flares outwardly or which is of frusto-conical shape. By means of any suitable apparatus this cup member 10 is then spun to form a. constricted or inwardly eX- tendingintermediate bead or neck 13 which is represented as located at substantially the center of the flaring or frusto-conical peripheral flange portion 12. This having been done, the partially formed cap is placed within other dies and pressure applied thereto to crush down or compress and flatten that portion of the flange or side wall 12 which is located between the disk-like portion 11 and the bead or neck 13, the material between these locations being forced into a flattenedout condition or folded onto itself as clearly indicated at 14C in Figure 3, 14 indicating what kwillbe the final top of the cap, this top including ,the original portion 11 and the squashed down or folded adjacent portion of the side. As a cap of this particular type is intended for use at ythe top of a post or pedes-I tal insulator upon which may be bolted a conductor clamp, bus bar support or switch structure, this flange 14 is represented as provided with a series of holes 15 which may be very readily drilled therein, drilling being preferable to punching though it is even possible that punching might be resorted to if desired. The cap is crimped at 16 for retaining purposes.

The cap having been formed as above described, it is intended to be cemented onto a porcelain body in the usual manner, the unfolded or remaining skirt or peripheral flange portion 12 in Figure 3 being embracingly engaged about an extension on the end of the porcelain body. The bus bar support, clamp or switch element is then placed upon the top of the flange 14 and bolted down byV suitable bolts passing through the holes 15. Of course it will be understood that in all three views the cap is shown as inverted as in actual practice it is obvious that it will be at the top of the insulator.

From the foregoing description and a study of the drawing it will be apparent that I have thus provided a novel one piece cap formed by stamping and spinning, the disadvantages of the cast or forged caps, brittleness in the first instance and expense in the second, being entirely avoided.

While I have shown and described a cap of a certain shape and proportions and have specified a certain sequence of steps for malri f ing the same it should of course be under stood that the disclosure is merely illustrative and that I reserve the' right to make whatever changes fall withinv the scope of the 5 claims hereunto appended.

Having thus described the invention, I claim:

l. The method of making a malleable in- I sulator cap comprising pressing a piece of 1U material into frusto-conical cup shape, spin-V ning the cup to deiine a constricted intermediate neck portion, and applying pressure to the cup to fold upon itself that portion of the material lying between said neck portion fand the closed end to form a flange overhanging the skirt portion.

2. The method of making a malleable insulator cap comprising pressing a piece of material into frusto-conical cup shape', spinnin the cup to define a constricted interme iate neck portion, applying pressure tov the cup to fold upon itself that portion of the material lying between said neck portion and the closed end to form a langeoverhanging the skirt portion, and forming holes in said overhanging flange portion.

3. The method of making a malleable one piece insulator comprising taking a piece of material, subjecting the same to the action of dies to press it into a rusto-conical cup shape,

Y spinning the` cup to form the same with an inwardly extending neck portion intermediate the open and closed ends, and subsequente ly compressing the cup to foldrupon itself the material between the constricted portion and the closed end while leaving the constricted portion unaffected.

' In testimony whereof I aiix my signature.

'4,0 BnirrrjerV A. PLiMrroNf 

